Examples of FilteredRowSet

javax.sql.rowset.FilteredRowSet

names from "Alpha" to "Bravo" will be returned} In the example above, we initialize a Range object which implements the Predicate interface. This object expresses the following constraints: All rows outputted or modified from this FilteredRowSet object must fall between the values 'Alpha' and 'Bravo' both values inclusive, in the column 'columnName'. If a filter is applied to a FilteredRowSet object that contains no data that falls within the range of the filter, no rows are returned.

This framework allows multiple classes implementing predicates to be used in combination to achieved the required filtering result with out the need for query language processing.

4.0 Updating a `FilteredRowSet` Object

The predicate set on a FilteredRowSet object applies a criterion on all rows in a RowSet object to manage a subset of rows in a RowSet object. This criterion governs the subset of rows that are visible and also defines which rows can be modified, deleted or inserted.

Therefore, the predicate set on a FilteredRowSet object must be considered as bi-directional and the set criterion as the gating mechanism for all views and updates to the FilteredRowSet object. Any attempt to update the FilteredRowSet that violates the criterion will result in a SQLException object being thrown.

The FilteredRowSet range criterion can be modified by applying a new Predicate object to the FilteredRowSet instance at any time. This is possible if no additional references to the FilteredRowSet object are detected. A new filter has has an immediate effect on criterion enforcement within the FilteredRowSet object, and all subsequent views and updates will be subject to similar enforcement.

5.0 Behavior of Rows Outside the Filter

Rows that fall outside of the filter set on a FilteredRowSet object cannot be modified until the filter is removed or a new filter is applied.

Furthermore, only rows that fall within the bounds of a filter will be synchronized with the data source. @author Jonathan Bruce

    }


    public void testPaging() throws Exception {
        insertMoreData(4);


        FilteredRowSet filteredRowSet = newFilterRowSet();


        filteredRowSet.setCommand("select * from USER_INFO");
        filteredRowSet.setUrl(DERBY_URL);


        filteredRowSet.setPageSize(3);
        filteredRowSet.execute();


        Predicate filter = new OddRowFilter();


        filteredRowSet.setFilter(filter);


        assertEquals("select * from USER_INFO", filteredRowSet.getCommand());


        assertFalse(filteredRowSet.previousPage());


        assertTrue(filteredRowSet.next());
        assertEquals(1, filteredRowSet.getInt(1));


        assertTrue(filteredRowSet.next());
        assertEquals(3, filteredRowSet.getInt(1));


        assertFalse(filteredRowSet.next());
        assertTrue(filteredRowSet.isAfterLast());


        if (!"true".equals(System.getProperty("Testing Harmony"))) {
            // RI need nextPage one more time
            assertTrue(filteredRowSet.nextPage());
        }


        int index = 5;
        while (filteredRowSet.nextPage()) {
            while (filteredRowSet.next()) {
                assertEquals(index, filteredRowSet.getInt(1));
                index += 2;
            }
        }


        assertEquals(9, index);


        filteredRowSet = newFilterRowSet();
        filteredRowSet.setCommand("select * from USER_INFO");
        filteredRowSet.setUrl(DERBY_URL);


        filteredRowSet.setPageSize(3);
        filteredRowSet.execute();


        filteredRowSet.setFilter(filter);


        assertTrue(filteredRowSet.next());
        assertEquals(1, filteredRowSet.getInt(1));


        assertTrue(filteredRowSet.nextPage());
        if (!"true".equals(System.getProperty("Testing Harmony"))) {
            // RI need nextPage one more time
            assertTrue(filteredRowSet.nextPage());
        }


        assertTrue(filteredRowSet.next());


        assertEquals(5, filteredRowSet.getInt(1));


        assertTrue(filteredRowSet.nextPage());


        assertTrue(filteredRowSet.next());
        assertEquals(7, filteredRowSet.getInt(1));


        assertFalse(filteredRowSet.nextPage());


    }

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